Abstract
Objective: Estimates of any protective effect of seat belts could be exaggerated if some crash survivors falsely claimed to police that they were belted in order to avoid a fine. The aim of this study was to determine whether estimates of seat belt effectiveness differed when based on belt use as recorded by the police and belt use determined by trained crash investigators.
Design: Matched cohort study.
Setting: United States.
Subjects: Adult driver-passenger pairs in the same vehicle with at least one death (n=1689) sampled from crashes during 1988–2000; data from the National Accident Sampling System Crashworthiness Data System.
Main outcome measure: Risk ratio for death among belted occupants compared with those not belted.
Results: Trained investigators determined post-crash seat belt use by vehicle inspections for 92% of the occupants, confidential interviews with survivors for 5%, and medical or autopsy reports for 3%. Using this information, the adjusted risk ratio for belted persons was 0.36 (95% confidence interval 0.29 to 0.46). The risk ratio was also 0.36 using police reported belt use for the same crashes.
Conclusions: Estimates of seat belt effects based upon police data were not substantially different from estimates which used data obtained by trained crash investigators who were not police officers. These results were from vehicles in which at least one front seat occupant died; these findings may not apply to estimates which use data from crashes without a death.
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Selected References
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- Braver E. R., Whitfield R., Ferguson S. A. Seating positions and children's risk of dying in motor vehicle crashes. Inj Prev. 1998 Sep;4(3):181–187. doi: 10.1136/ip.4.3.181. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cummings Peter, McKnight Barbara, Rivara Frederick P., Grossman David C. Association of driver air bags with driver fatality: a matched cohort study. BMJ. 2002 May 11;324(7346):1119–1122. doi: 10.1136/bmj.324.7346.1119. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Evans L. Double pair comparison--a new method to determine how occupant characteristics affect fatality risk in traffic crashes. Accid Anal Prev. 1986 Jun;18(3):217–227. doi: 10.1016/0001-4575(86)90006-0. [DOI] [PubMed] [Google Scholar]
- Evans L. The effectiveness of safety belts in preventing fatalities. Accid Anal Prev. 1986 Jun;18(3):229–241. doi: 10.1016/0001-4575(86)90007-2. [DOI] [PubMed] [Google Scholar]
- Farrington C. P. Relative incidence estimation from case series for vaccine safety evaluation. Biometrics. 1995 Mar;51(1):228–235. [PubMed] [Google Scholar]
- Greenland S. Interpreting time-related trends in effect estimates. J Chronic Dis. 1987;40 (Suppl 2):17S–24S. doi: 10.1016/s0021-9681(87)80005-x. [DOI] [PubMed] [Google Scholar]
- Greenland S. The effect of misclassification in the presence of covariates. Am J Epidemiol. 1980 Oct;112(4):564–569. doi: 10.1093/oxfordjournals.aje.a113025. [DOI] [PubMed] [Google Scholar]
- Robertson L. S. Estimates of motor vehicle seat belt effectiveness and use: implications for occupant crash protection. Am J Public Health. 1976 Sep;66(9):859–864. doi: 10.2105/ajph.66.9.859. [DOI] [PMC free article] [PubMed] [Google Scholar]